wondering what others are running for rear end gears...im thinking 4.56 maybe too low and 4.11 to high ... any ideas ??

 

You want to try and maximize your power-band while minimizing the number of times you have to shift gears. With that said, a lower rear gear (3.42, 3.73, etc.) should be used to make your transmission gear spread wider.

I put 3.42s in my 12-bolt and I can run most configurations in 1 or 2 gears. With my 3.73s I was having to downshift and upshift more often as I ran out
of gear. I cam'd/intake'd my motor for a broad powerband also (2K->7K) so I use the engine RPMs to complement the gears.

YMMV

 

im running 3.42 gears now and dont seem to be able to launch out of the corner. my cam is for low rpm torque...somthing like 1500 to 3000. do you think that could be my biggest problem?
thanks

 

What trans gear are you in coming out of the corners? What Intake do you run? What's your car weight? If the cam is not matched to the intake, you may have trouble, especially if the car is heavy. Run your RPM/MPH numbers using a 3.73 gear, it might be the sweet-spot for you.

 

A General rule of thumb is to gear the car to top out at around 70 MPH in whatever gear your are planning on running. I have 3.42 gears, first gear is 2.42 and have 27 inch tall tires. I have never been out of first on an autocross course but I have also seen over 7000 RPM on occasion. I also don't have a lack of power coming out of slow corners and I don't have a torque grind cam in the car.

 

Do you autox with a TH350 automagic? If so, you can afford to gear down a tad more since the converter will cushion your low-rpm behavior. After swapping my 700r4 for the T56, you really have to watch for stalling around slow corners more and have to downshift around really slow ones.

 

I do have a TH350, with a tight OEM convertor.

 

most of the time im running 2nd gear...but at the hill climbs i run 3rd with 1 or 2 corners that i have to shift down for and 1 place i need 4th. my intake is a stock duel plane winters off of a corvette i think. im probably close to stock wieght, i have stripped it down but then i put in a roll bar/subframe connector. not sure what you mean by run the rpm/mph numbers...
thanks for the info

 

any body else have thoughts on this?

 

http://www.kabamus.com/garage/gears.html

I think this is what he means. Its a calculator to see what your would be at a given rpm in each gear.